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[PATCH] xfs: remove pointless pointer increment in xfs_dir2_block_compac

To: xfs-oss <xfs@xxxxxxxxxxx>
Subject: [PATCH] xfs: remove pointless pointer increment in xfs_dir2_block_compact()
From: Eric Sandeen <sandeen@xxxxxxxxxx>
Date: Wed, 09 Apr 2014 15:30:49 -0500
Delivered-to: xfs@xxxxxxxxxxx
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.4.0
xfs_dir2_block_compact() is passed a pointer to *blp, and
advances it locally - but nobody uses the pointer (locally)
after that.

This behavior came about as part of prior refactoring,

20f7e9f xfs: factor dir2 block read operations

and looking at the code as it was before, it seems quite clear
that this change introduced a bug; the pre-refactoring code
expects blp to be modified after compaction.
And indeed it did; see this commit which fixed it:

37f1356 xfs: recalculate leaf entry pointer after compacting a dir2 block

So the bug was introduced & resolved in the 3.8 cycle.

Whoops.  Well, it's fixed now, and mystery solved; just remove
the now-pointless local increment of the blp pointer.

(I guess we should have run clang earlier!)

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---

diff --git a/fs/xfs/xfs_dir2_block.c b/fs/xfs/xfs_dir2_block.c
index 4f6a38c..5259939 100644
--- a/fs/xfs/xfs_dir2_block.c
+++ b/fs/xfs/xfs_dir2_block.c
@@ -319,7 +319,6 @@ xfs_dir2_block_compact(
                (xfs_dir2_data_aoff_t)((char *)blp - (char *)hdr),
                (xfs_dir2_data_aoff_t)((be32_to_cpu(btp->stale) - 1) * 
sizeof(*blp)),
                needlog, &needscan);
-       blp += be32_to_cpu(btp->stale) - 1;
        btp->stale = cpu_to_be32(1);
        /*
         * If we now need to rebuild the bestfree map, do so.

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